1. Field of the Invention
The present invention relates generally to compounds which have more than one pharmaceutically desirable activity. More particularly, the present invention is directed to a newly isolated indole alkaloid compound and analogs thereof which have been found to be effective antiinflammatory agents while also being useful as ultraviolet radiation absorbers, i.e. UV protective agents.
2. Description of Related Art
A yellow-green pigment was first isolated from sheathed cyanobacteria in the late 1870's. Although the pigment included a complex mixture of unidentified compounds, the single term "scytonemin" was introduced to identify the pigment. Since its initial discovery, scytonemin has been isolated and identified in more than 30 species of sheathed cyanobacteria. These sheathed bacteria which contain scytonemin have been found in diverse geographic regions wherever exposure to strong solar irradiance occurs. These regions have included freshwater, terrestrial and marine habitats.
An important characteristic of the scytonemin pigment is its ability to absorb ultra-violet (UV) radiation. Sheathed cyanobacteria or similar ancestral forms occur commonly as microfossils in strata of biogenic origin from the Proterozoic period and even earlier. Since UV fluxes were considerably higher then than now, it is likely that development of scytonemin for its UV-screening properties was important to the evolution of cyanobacteria. The scytonemin pigment absorbs most strongly in the UV-A spectral region. There is also significant absorbance in the UV-B region.
Although scytonemin pigment has been known as a UV absorber for many years, the various complex group or groups of compounds which are present in the pigment have not been completely isolated or identified. Accordingly, the specific ingredient or ingredients in scytonemin pigment which provide it with such strong UV absorbing properties have remained unknown.